All three source indications of the tempo-character are almost certainly authentic (vivace and assai – certainly, non tanto – highly likely). It means that Chopin changed his mind on this issue at least twice, yet the order of the changes is unknown – we only know that assai is later than vivace, as in GC there is a relevant correction. Chopin's hesitation concerned rather terminology than the actual tempo of the Etude, as the later added metronome tempo is the same for all three indications. The choice of one of them is then of a minor practical meaning. In the main text we give assai, with which Chopin replaced vivace, which seems to correspond better to the fast (for the rhythm and texture used in the Etude) tempo indicated by the metronome.
Compare the passage in the sources »
category imprint: Differences between sources; Corrections & alterations
issues: Chopin's hesitations, Authentic corrections in GC
notation: Verbal indications